Microporous materials, including zeolites and silicoaluminophosphates, are widely used in the petroleum industry as to absorbents, catalysts and catalyst supports. Their crystalline structures consist of three-dimensional frameworks of tetrahedral atoms containing uniform pore openings, channels and internal cages of dimensions (<20 Å) similar to most hydrocarbons. The composition of the frameworks can be such that they are anionic, which requires the presence of non-framework cations to balance the is negative charge. These non-framework cations, such as alkali or alkaline earth metal cations, are exchangeable, and if converted to the proton form, impart the material with Brønsted acid sites having catalytic activity. The combination of acidity and restricted pore openings gives these materials catalytic properties unavailable with other materials due to their ability to exclude or restrict some of the products, reactants, and/or transition states in many reactions. Non-reactive materials, such as pure silica and aluminophosphate frameworks are also useful and can be used in absorption and separation processes of reactive molecules such as alkenes.
The family of crystalline microporous compositions known as molecular sieves, which exhibit the ion-exchange and/or adsorption characteristics of zeolites are the aluminophosphates, identified by the acronym AlPO, and substituted aluminophosphates as disclosed in U.S. Pat. Nos. 4,310,440 and 4,440,871. U.S. Pat. No. 4,440,871 discloses a class of silica aluminophosphates, which are identified by the acronym SAPO and which have different structures as identified by their X-ray diffraction pattern. The structures are identified by a numerical number after AlPO, SAPO, MeAPO (Me=metal), etc. (Flanigen et al., Proc. 7th Int. Zeolite Conf., p. 103 (1986) and may include Al and P substitutions by B, Si, Be, Mg, Ge, Zn, Fe, Co, Ni, etc.
ExxonMobil and others extensively use various microporous materials, such as faujasite, mordenite, and ZSM-5 in many commercial applications. Such applications include reforming, cracking, hydrocracking, alkylation, oligomerization, dewaxing and isomerization. Any new material has the potential to improve the catalytic performance over those catalysts presently employed.
There exists the need for new structures, having different properties than those of known materials, for improving the performance of many hydrocarbon processes. There are currently about 191 known microporous framework structures as tabulated by the International Zeolite Association. Each structure has unique pore, channel and cage dimensions, which gives its particular properties as described above. ITQ-40 is a new framework material.